Chain heal is the ultimate heal. Other healing classes could only wish they had something so cool, but I can do MT healing as well. Though it bothers me a pally can crit higher than me (though he was using his trinkets, I was not), even when I have like 400 more healing than him. I used to not use chain heal much, but learn to use it. Great on fights when you have rogues taking damage such as the Maiden fight in karazhan. Other fights such as Prince and Nightbane require lots of main tank healing. Esp in phase 2 of Prince, you can't even think about getting 5 seconds not casting, so you need good mp5 (though mana pool is more important). For heavy hitters like that grace of air totem (the one that raises agility by 77) helps improve the main tanks dodge by more than 2%. Helps keep him alive in Prince phase 2. In that fight you will find yourself using healing wave only. You could consider downranking, but I just used max healing wave. I'd usually pop earth shield on tank at around 61% in that fight as well, and mana tide at 30%.
But there are a decent number of boss fights you will be outside the 5 sec rule, so it is nice to have some decent spirit mana regen. But don't go for gear with spirit on it (that's just a bonus), that's mainly priest/druid gear. Go for +healing, mp5, and Intelligence (for mana pool and additional +healing). Stam is nice as well.
Keep water shield up always. Only time you may not want to is when you anticpate needing a heal on the tank in the next 1.5 secs. But generally you aren't being hit, and it's easy to keep up.
Did I mention chain heal? Yes. use it. Even if it's only healing 2 targets or pets.
You will mainly be using max rank healing wave and chain heal. For small heals I use rank 8 healing wave or lesser healing wave (when the mage aoe's). In fact, I sometimes put earth shield on the mage when we do the AOE pulls in Kara and spam lesser healing wave on mage.
I did contemplate spamming rank 2 healing wave to keep healing way up, but it doesn't seem worth it to me (even though it burns no mana). I worry about getting caught in a wimpy heal when the tank takes massive damage. Yes you can alway cancel it, but I prefer to cast max rank healing wave and cancel if I don't need it. On some fights such as Nightbane (phase 1), Prince phase 2 I like to always have a healing wave being cast. Cancel if not needed.
The rest just comes from experience. But you can check out this webpage, it has some hardcore sh*t, and cool macros. I love having nature's swiftness on a macro. I used to not use it much because I had trouble hitting 2 buttons real quick. But now I have nature's swiftness/max healing wave macro on my #4 button. Easy to hit fast.
http://elitistjerks.com/f31/t19181-shaman_how_heal_like_pro/
Edited, Feb 3rd 2008 2:56pm by thrashering